1. Field of the Invention
The present invention relates to a novel transition metal complex where a monocyclopentadienyl ligand to which an amine-based group is introduced is coordinated, a method of synthesizing the same, and olefin polymerization using the transition metal complex, and more particularly, to a novel transition metal complex containing a phenylene group that does not form a bridge, a method of synthesizing the same, and olefin polymerization using the transition metal complex.
2. Description of the Related Art
In the early 1990s, Dow Co. developed Me2Si(Me4C5)NtBuTiCl2 (Constrained-Geometry Catalyst, hereinafter referred to as CGC) (U.S. Pat. No. 5,064,802). CGC shows excellent properties in a copolymerization reaction of ethylene and alpha-olefin, compared to conventional metallocene catalysts. For example, (1) CGC can be used to form high molecular weight polymers due to its high reactivity at high polymerization temperature, and (2) CGC can be used for copolymerization of alpha-olefin having large steric hindrance, such as 1-hexene and 1-octene. Due to many useful properties, in addition to these properties described above, obtained from use of CGC, research into synthesis of CGC derivatives as a polymerization catalyst is substantially increasing in academic and industrial fields.
For example, synthesis of metal complexes, instead of a silicon bridged CGC, comprising various other bridges and a nitrogen substituent, and polymerization using these metal complexes were performed. Examples of such metal complexes include Complexes 1 through 4 (Chem. Rev. 2003, 103, 283).

Complexes 1 through 4 respectively contain a phosphorus bridge, an ethylene or propylene bridge, a methylidene bridge, and a methylene bridge, instead of the silicon bridge of the CGC structure. However, these complexes show low activity or poor copolymerization performance when ethylene is polymerized or when ethylene and alpha-olefin are copolymerized, compared to CGC. Due to these problems, these complexes are difficult to be applied to commercial processes.
On the other hand, only a few kinds of Group 4 transition metal complexes having monocyclopentadienyl ligand at which no bridge is formed were developed for use in ethylene polymerization or copolymerization of ethylene and alpha-olefin. Examples of the transition metal complex having monocyclopentadienyl ligand at which no bridge is formed include Me4 CpTiX2(OAr) where X is halide and Ar is aryl, RnCpTiX3 where R is alkyl, aryl, or a fused ring, and X is halide, alkyl, or alkoxy. Recently, professor Nomura et al. developed Me4 CpTiX2(OAr), which is a cocatalyst such as methylalumoxane (MAO), effectively promoting homopolymerization of ethylene and copolymerization of ethylene and 1-hexen (Macromolecules 2002, 35, 5388) when being activated. However, compared to L1L2TiX2, a piano-stool shaped compound, such as RnCpTiX3 is unsuitable for polymerization of ethylene or copolymerization of ethylene and alpha-olefin, rather suitable for synthesizing syndiotactic polystyrene (sPS) (European Patent No. 210615 (1987), Macromolecules 1986, 19, 2464). In addition, a metal compound prepared by substituting a cyclopentadienyl ring of RnCpTiX3 with an electron donor, such as NMe2, was developed. However, the metal compound shows a low degree of ethylene homopolymerization activity (J. Polym. Sci. Polym. Chem. 1998, 36, 319).
Accordingly, these is a need to develop a catalyst having high polymerizaition performance using a Group 4 transition metal complex having a monocyclopentadienyl ligand at which no bridge is formed.